Device with independent hydraulic control to transmit measurements taken at the bottom of a well

ABSTRACT

A hydraulically controlled device to transit measurements taken at the bottom of a well to the surface, by means of pressure impulses created by periodical restrictions on the passage of the drilling fluid, consisting of means to control these restrictions, operated by electrical impulses, a hydraulic fluid circuit to operate the means restricting the passage of the drilling fluid, a turbine driven by the drilling fluid and a hydraulic fluid pump fixed on the same shaft, characterized by the fact that the said pump is placed in a hydraulic fluid circuit containing passages to discharge the fluid on either side of a double-action hydraulic jack, to which said restricting means is mechanically connected, and an accumulator is mounted in said circuit in parallel with said jack.

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1Jted States Patent 1 -Quichaud et a1. 1 1 Sept. 4, 1973 [54] DEVICEWITH INDEPENDENT HYDRAULIC 3,302,457 2/1967 Ma es 73/152 CONTROL TOTRANSMIT MEASUREMENTS TAKEN AT THE BOTTOM OF A WELL Primary ExammerJerryW. Myracle Att0rney1-Iolcombe, Wetherill & Brisebois [75] Inventors:Claude Quichaud, Pau-Billere;

Jean-Pierre Le, Peuvedic, Pau, both of France [73] Assignee: SocieteAnonyme dite: Societe [57] ABSTRACT Nationale Des Petroles, DAquitaine,Courbevoie, France A hydraulically controlled device to transitmeasurements taken at the bottom of a well to the surface, by Filed; y14, 1971 means of pressure impulses created by periodical re- [21] ApplNo 162,558 strictions on the passage of the drilling fluid, consistingof means to control these restrictions, operated by electrical impulses,a hydraulic fluid circuit to operate the [30] Apphcatlo Pnonty Datameans restricting the passage of the drilling fluid, a tur- July 16,1970 France 7026213 bine driven by the drilling fluid and a hydraulicfluid pump fixed on the same shaft, characterized by the fact [52] US.Cl. 73/151 that the said pump is placed in a hydraulic fluid circuit[51] Int. Cl E2lb 47/12 containing passages to discharge the fluid oneither side [58] Field of Search 73/155, 151, 152; of a double-actionhydraulic jack, to which said re- 175/48 stricting means is mechanicallyconnected, and an accumulator is mounted in said circuit in parallelwith [56] References Cited said jack.

UNITED STATES PATENTS 2,964,116 12/1960 Peterson 175/48 5 Claims, 2Drawing Figures 57- l 22 Z %22 GS 3 Patented Sept. 4, 1973 1 H H 3 mm MW 4 8 7 ////7/////// 7 7/ 7////2//Z%//////Z/% 7/ 7 7//////// 47/ M B 6 w1 DEVICE WlITll-KINDEENDENT HYDRAULIC CONTRQL T TRANSMKT MEASUREMENTSTAKEN AT THE BOTTOM OF A WELL The present invention concerns a devicewith independent hydraulic control, used to transmit signalsrepresenting measurements taken at the bottom of a well to the surface.

During the drilling of a well, it is very useful to know numerousvariables such as the resistivity of the layers being traversed, thehardness of the rock, wear or deviation in the drilling tool, the momentand weight to which it is subject, and its rotating velocity, withoutinterrupting drilling operations. Such information can be used toexamine and adjust drilling conditions. lProcesses already exist forautomating drilling by the measured use of data picked up duringdrilling by sensing devices which convert the physical quantity measuredinto an electrical signal.

Transmission of such information from the bottom of the well to thesurface presents difficulties. The use of electrical cables to conveythe electrical signals resulting from conversion of the data picked upby the sensors or inclinometer is incompatible with rotary drilling,because of the considerable difficulty of installing a continuous cablein a sectional drilling column, and the complications it involves in theoperations needed to replace worn tools.

On the other hand, the flow of drilling fluid normally discharged insidethe collars carrying the tool can form a suitable fluid medium fortransmission of signals, by means of pressure variations created at thebottom of the well, without disturbing ordinary drilling operations.

Up till now research has been concentrated on designing more or lesscomplex devices intended to produce series of hydraulic impulses in thedrilling fluid representing a physical measurement taken at the bottomof the well during drilling. A common feature of all these inventions isthe lack of power in the well-bottom transmitting device, whichgenerally makes it hard to distinguish the signals on the surface,against the background noise of the pumps, and which has prevented mostof them from being developed commercially.

The present invention is designed to provide a solution to thisdrawback, by making appropriate use of the amount of power available inthe hydraulic fluid. More specifically, it concerns a device withindependent hydraulic control, designed to transmit to the surfacesignals representing measurements taken at the bottom of the well, inthe form of pressure impulses created by regular restrictions on thepassage of the drilling fluid, consisting of an appliance controllingthe regular restrictions of the passage of the drilling fluid, operatedby the electrical impulses connected with the measurement signals, ahydraulic fluid circuit being used to operate, through the saidhydraulic control, a doubleaction hydraulic jack connected mechanicallyto means of restricting periodically the passage of the drilling fluid,a turbine driven by the drilling fluid and a hydraulic fluid pressurepump attached to the same shaft, characterized by the fact that the saidpump is placed in a hydraulic fluid circuit containing passages todischarge the fluid on either side of a double-action hydraulic jack, towhich is mechanically connected an appliance to restrict the passage ofthe drilling fluid.

The invention is more specifically characterized by the hydraulic fluidcircuit including the said pump discharging fluid under pressure, bymeans of a control appliance such as a slide-valve or electro-valve oneither side of the piston of a double-action hydraulic jack connectedmechanically to an appliance to restrict the passage of the drillingfluid.

The advantages of the present invention lie in the combination of anaxial turbine and a hydraulic fluid pressure-pump, and also in theparticular lay-out of the hydraulic fluid circuit.

The turbine supplies a large amount of mechanical power from thedrilling fluid and is compatible with the equipment generally used indrilling wells. A hydraulic oil-pressure pump is a light, compact,powerful hydraulic generator, perfectly suited to the requirements ofdrilling equipment, and also used in aeronautical construction, underunfavourable environmental conditions The energy transmitted by such apump is used to control the restriction appliance, ensuring perfectreliability of functioning, and with high efficiency, in combinationwith a double-action jack.

The application of the double-action jack makes the operation of therestriction appliance more reliable than is the case in earlier systems,since the energy required to operate it comes entirely from thehydraulic fluid pressure pump, so that it is more or less independent ofconstraints occurring when the mud energy is used directly in thehydraulic fluid control circuit, notably because of pressure andcompositional variations.

The lay-out of the hydraulic fluid circuit operating the double-actionjack allows the fluid under pressure to be discharged, depending on theposition of the control appliance such as an electro-valve, either onthe upward or downward side of the jack controlling the means ofrestricting the passage of the drilling fluid.

According to one recommended embodiment, the pressure pump is connected,in shunt, to an accumulator of hydraulic fluid under pressure,consisting of one or more pistons housed in cylinders and receiving, onone side, the fluid discharged by the pump, and with the other sidecommunicating with the suction inlet of the pump and simultaneouslypushed back by one or more prestressed springs.

This embodiment may include a fluid-pressure limiter, consisting of avalve-needle closing an aperture connecting the pump discharge and pumpintake points, subject to the discharge pressure of the pump and pushedin the opposite direction by the thrust from a spring with adjustablecalibration; when pressure is too high, this limiter allows the oil topass directly from the discharge side of the pump to the intake side.

The intake pressure of the pump may be transmitted to a mobile surface,in the form of a compensating piston, for instance, the other side ofwhich is subjected to the pressure of the drilling fluid, so as to allowthe oil to expand and to compensate the apparent variation in totalvolume resulting from displacement of the jack rod operating thepassage-restriction appliance.

The device according to the present invention is illustrated by, withoutbeing confined to, the example of its embodiment shown in theaccompanying figures.

FIG. 1 shows a special ballast-rod containing the well-bottom hydraulicinstallation with the turbine supplying the energy. This collarpossesses end threads in conformity with API standards, and can beassembled easily at any point on the drilling line, preferablyimmediately next to the drilling tool.

FIG. 2 represents the hydraulic power circuits needed to operate thecomponents such as flap-, clackor other valves or needle-valvesproducing restrictions on the circulation of the drilling mud.

The special collar containing the bottom hydraulic installation shown inFIG. 1 contains ends(2)which have standardized threads for assembly inthe drilling line, a wide bore compatible with these threads anddesigned to hold the internal fittings, and a shoulder (11) to supportthese fittings.

The internal fittings are contained in a watertight tube (3) linking theturbine (4) with the restriction appliance or valve (5). The annularspace left free between the bore in the collar (1) and watertight tube(3) allows the drilling fluid to pass from the valve (5) to the turbine(4).

The fixed blades ('7) and mobile blades (8) of turbine (4), which is ofstandard type, are held by the nuts 9 and 10 respectively in the casingof the turbine (4) on the shaft (6), which has a suitable shoulder.

The drilling fluid penetrates into the fixed blades through a series ofapertures situated at the top of the casing (4), and comes out axiallyat the bottom of the turbine, providing the standard irrigation of thedrilling tool.

The shaft (6) of the turbine, held by the thrust-block (13) directlydrives the shaft (24) of the controlling fluid pump at the lower end ofthe hydraulic circuit, through a watertight passage (12), and in certaincases also drives an independent electricity supply apparatus, such as asmall alternator (14).

The central part of the tube (3), shown in detail in FIG. 2, containsthe well-bottom hydraulic installation, from which emerges the drivingrod (57) of the needlevalve (16), acting with the seat to producerestrictions on the passage of the mud column. The invention is notconfined to the use of a needle-valve acting with a seat, sincehydraulic operation of the jack-rod(57) allows other methods ofrestriction to be used, such as dome-valves or balanced valves withmultiple seats.

FIG. 2 shows one embodiment of the hydraulic power device to operate therestriction valve. This figure clearly shows how the device operates.The watertight tube (3) contains all the hydraulic components, heldbetween an upper shoulder (65) and the upper end (61) of the turbinecasing (4), which is screwed into the tube (3). From bottom to top arethe hydraulic pump (25), the limiter casing (30) containing the freepiston (31), the accumulator casing (41), the base (53) of theslide-valve or electro-valve shown here diagrammatically (50), the cover(54) and the jack (55). All these components are cylindrical in form, soas to fit perfectly inside the tube (3), and possess, on their plane endsurfaces, communication openings equipped with sealing devices such asO-rings. This lay-out allows use to be made of single-piece cylindricalunits which can withstand all drilling impacts and vibration, and whichare small enough in diameter to be compatible with normal well-bottomequipment. In order to reduce vibration forces, these components arepreferably made from aluminium-based light alloys, which have theadvantage of being small in mass and with a good heat-transfercoefficient. The machining of housings for various parts and drilling ofpipes are carried out in the mass of the components, the outsideapertures of the passages used for this work being blocked subsequentlywith plugs (33), if the hydraulic circuit requires this.

The pump (25) is of the gear type (28), carried on bearings (27) andwith a sealing device (26) on the shaft (24), but the invention is ofcourse not confined to the use of this type of pump. It sucks in thedriving fluid, for instance the oil in the reservoir (34) of the limitercasing (30), directly connected with the reservoir (47) of theaccumulator casing (41) by the pipe (64). The reservoir (34) contains afree piston in the form of a compensating piston (31), the other side ofwhich is in communication with the drilling fluid under pressure,through the opening (35). The purpose of this free piston is to allowthe oil or other driving fluid to expand, and to compensate the apparentreduction in total volume resulting from the movement of the jackrod(57).

Immediately above the reservoir (34) is the adjustable pressure-limitingdevice. The pump (25) discharges the fluid under pressure into thepassage (32) and into the seat (36), closed by the needle (37) of thislimiter. When pressure reaches a pre-set level, the force on the needle(37) balances the force of the spring (38) wound up by the screw (39).The needle then tends to open, to allow part of this pressure fluid toreturn to the reservoir (34). An increase in the flow of the pump (25),resulting for instance from an increase in the velocity of the turbine,does not produce any increase in pressure, because of this diversion ofthe flow by the limiter.

The fluid under pressure discharged into the passage 32 next passesthrough the filter 40, which retains any impurities that could affectthe functioning of the slidevalve (50).

The filtered fluid is directed into a pressure reservoir (48), throughthe passage 44. This reservoir is contained in the accumulator, which isconstructed in the form of a cylindrical block and is in contact withone or more pistons (42) sliding inside a cylinder-block (41) andsubject on one side to the discharge pressure of the pump and on theother to the intake pressure of the pump, increased by the force of oneor more prestressed springs (43). The upper end of the reservoir (43) isclosed by a plug (45). The accumulator unit is constructed in the sameway as the limiter. In particular, the pressure fluid channels (44) andfluid return channels (46), and the cylinders and accompanying channels,are machined directly in a block of metal, which may be a lightaluminium alloy.

Above the accumulator under pressure is a base (53), to which isattached the distributor component shown diagrammatically here (50), andwhich may be a slide-valve or electro-valve.

The controljack for the restriction appliance consists ofa cylinder (55)and piston (56) operating a rod (57). The piston (56) can move eitherupwards or downwards, depending on whether the fluid pressure isconveyedbelow or above the piston. The passages 51 and 52 connect thetwo sides of the piston with the distributor, providing thispossibility.

The distributor is a component controlled by an electrical signal whichcan act on two separate windings. When one of these windings is excited,it provides communication between the fluid under pressure and one sideof the jack piston, on the one hand, and between the fluid sucked in bythe pump and the other side of the piston, on the other hand. If theother winding is excited, communications are reversed, and the pistoncan move in the other direction. if neither winding is excited, there isno communication, and the piston cannot move.

The discharge from the pump (25), driven continuously by the turbine,driven in turn by the drilling fluid, keeps the reservoir (48) filledwith driving fluid under pressure, which, in the event of exceeding ofthe pressure threshhold, circulates through a diversion, by means of thepressure limiter (37), the adjustable calibrated spring of which allowsthe threshhold to be regulated.

Data, concerning the rock hardness, for instance, are collected withsensing devices, not shown here, situated near the drilling tool, andconverted into electrical signals representing the measured quantities.

These signals are processed or coded in electronic circuits contained inwatertight enclosures (22), and supplied with electrical energy bylow-powered independent means such as a small alternator (14), alsodriven by'the turbine (4). This processing or coding produceslow-powered electrical impulses which can operate the hydraulic fluidcontrol appliance. To create a hydraulic impulse in the form of amomentary increase in the pressure of the drilling fluid, the circuitscontained in the enclosures (22) deliver a brief electrical impulseapplied to the distributor winding (50), controlling displacement of thejack to the position which causes a sharp restriction, followed after amoment by a second electrical impulse, also brief in duration, which isapplied to the other distributor winding and causes the jack to returnto the position where it causes no restriction. These electricalimpulses, coded or uncoded, are transmitted along wires (58), whichtraverse the cylinder block (55) to the hydraulicfluid controllingappliance, such as the windings of the distributor (50). This opens upaccess in turn for the fluid to each side of the piston (56) of the jack(55). The movement of the piston causes the needle (16), fixed to thepiston, to close and open in turn. Because of the effect of the spring(43), which stores up the energy supplied by the pump (25), the piston(56) is operated forcefully and rapidly in both directions, causing asharp, momentary restriction on'the flow of drilling fluid circulatinginside the drilling line, in the form of a pressure impulse, which istransmitted to the surface, where it is detected.

What is claimed is:

ll. A device for transmitting to the surface signals representingmeasurements supplied as electrical impulses by a measuring instrumentlocated within a well, said signals consisting of pulses in the pressureof a drilling fluid in said well, which pulses are created by temporaryrestrictions in the flow of said fluid, said device comprising:

means for restricting the flow of said fluid,

a double-acting hydraulic jack connected to operate said restrictingmeans,

a turbine driven by said drilling fluid,

a fluid pressure pump driven by said turbine,

a hydraulic fluid circuit supplied by said pump and connected to applythe pressure produced by said pump to either side of said jack,

means in said fluid circuit responsive to said electrical impulses forcontrolling the side of said jack to which pressure is applied, and

a pressure accumulator comprising a spring-biassed piston connected insaid hydraulic circuit in parallel with both said jack and pump.

2. A device according to claim 1, comprising a fluid pressure limiterconsisting of a needle-valve closing an aperture which connects the pumpdischarge and intake, said needle valve being subject to pressureloading in one direction by the discharge pressure of the pump andbiassed in the opposite direction by spring means.

3. A device according to claim 2 comprising means for adjusting thepressure exerted on said needle valve by said spring means.

4. A device according to claim 1, in which the intake pressure of thehydraulic fluid pump is transmitted to one side of a movable piston, theother side of which is subject to the pressure of the drilling fluid.

5. A device according to claim 1, in which the means restricting theflow of thefluid is a needle-valve attached to the piston of said jackand cooperating with a suitable seat in the flow path of said fluid.

1. A device for transmitting to the surface signals representingmeasurements supplied as electrical impulses by a measuring instrumentlocated within a well, said signals consisting of pulses in the pressureof a drilling fluid in said well, which pulses are created by temporaryrestrictions in the flow of said fluid, said device comprising: meansfor restricting the flow of said fluid, a double-acting hydraulic jackconnected to operate said restricting means, a turbine driven by saiddrilling fluid, a fluid pressure pump driven by said turbine, ahydraulic fluid circuit supplied by said pump and connected to apply thepressure produced by said pump to either side of said jack, means insaid fluid circuit responsive to said electrical impulses forcontrolling the side of said jack to which pressure is applied, and apressure accumulator comprising a spring-biassed piston connected insaid hydraulic circuit in parallel with both said jack and pump.
 2. Adevice according to claim 1, comprising a fluid pressure limiterconsisting of a needle-valve closing an aperture which connects the pumpdischarge and intake, said needle valve being subject to pressureloading in one direction by the discharge pressure of the pump andbiassed in the opposite direction by spring means.
 3. A device accordingto claim 2 comprising means for adjusting the pressure exerted on saidneedle valve by said spring means.
 4. A device according to claim 1, inwhich the intake pressure of the hydraulic fluid pump is transmitted toone side of a movable piston, the other side of which is subject to thepressure of the drilling fluid.
 5. A device according to claim 1, inwhich the means restricting the flow of the fluid is a needle-valveattached to the piston of said jack and cooperating with a suitable seatin the flow path of said fluid.